Low-cost mobile handheld devices require stable and clear entertainment video and audio reception, as well as high digital data rates. Circular polarization of broadcast signals reduces dependence on receiving antenna orientation for received signal strength, so that a simple dipole in virtually any orientation, for example, can receive a usable signal.
As in other broadcasting, it can be desirable to achieve particular extents of signal reception range, and to employ a small number of minimally-powered transmitters in the course of realizing that propagation. To these ends, radiating devices are preferably capable of exhibiting high gain and are preferably configurable with any of a variety of directionality options. Along with gain and propagation pattern, light weight and relatively small size may ease strength and wind load requirements for tower construction, allowing extra height above average terrain (HAAT), more bays, more radiators per bay, and the like.
Many broadcast antenna configurations exist. Configurations usable and of merit for many applications include elements referred to as patch radiators, positioned parallel to and separated from conductive backplanes. Typical known patch-radiator-based antennas are directional to a greater or lesser extent, and can produce a single pronounced lobe of emission in a principal direction (zero degrees relative to an axis perpendicular to the radiator centroid and directed away from the backplane), with emission to the sides (+/90 degrees with respect to the principal direction) and to the rear (180 degrees with respect to the principal direction) that decreases with increasing backplane size. Depending on details of design, individual patch antennas can be equally directional in azimuth and elevation, and can be configured in arrays that modify directionality.
Deficiencies in existing antenna designs for several broadcasting bands, including the 1.4 GHz band, may include excessive cost, narrow bandwidth capability (i.e., poor voltage standing wave ratio (VSWR), failure to extend over an entire allotted band, or even a substantial fraction thereof), lack of support for high broadcast transmitter power, variable and high wind load, and limited ability to provide circular polarization.
Some existing high power (up to 1 kW) circularly polarized antennas for bands near the 1.4 GHz band include crossed dipoles, log periodic radiators, slotted coaxes, and other styles. These styles can be so demanding to manufacture as to result in high cost for the achieved performance. They can also demand unique configurations for each unique propagation pattern. A generic style of circularly polarized antenna that allows diverse configuration and simplified installation could potentially achieve a much lower installed cost than available products without sacrifice of performance or reliability.